Sahar BokosmatyA teaching experiment was conducted to explore the impact of Cabri Geometry on 6 Year 7 students’ understanding of parallelograms. Students worked in pairs, and were guided through activities designed to introduce the software and to encourage discovery and exploration of specific geometric properties. Students were also required to use this knowledge to solve geometric problems. Over several lessons, data were collected via taperecorded observations of student interactions and discussions, work samples, and test results. The dynamic investigation promoted deeper understanding of the underlying geometric properties of parallelograms and students’ abilities to solve geometric problems.